LM386 Low Voltage Audio Power Amplifier
General Description
The LM386 is a power amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but the addition of an external resistor and capacitor between pins 1 and 8 will increase the gain to any value from 20 to 200.The inputs are ground referenced while the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 milliwatts when operating from a 6 volt supply, making the LM386 ideal for battery operation.

Electrical Characteristics (Notes 1, 2)
TA = 25˚C Parameter Operating Supply Voltage (VS) LM386N-1, -3, LM386M-1, LM386MM-1 LM386N-4 Quiescent Current (IQ) Output Power (POUT) LM386N-1, LM386M-1, LM386MM-1 LM386N-3 LM386N-4 Voltage Gain (AV) Bandwidth (BW) Total Harmonic Distortion (THD) Power Supply Rejection Ratio (PSRR) Input Resistance (RIN) Input Bias Current (IBIAS)VS = 6V, Pins 2 and 3 Open
Note 1: All voltages are measured with respect to the ground pin, unless otherwise specified. Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electricalspecifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance. Note 3: For operation in ambient temperatures above 25˚C, the device must be derated based on a 150˚Cmaximum junction temperature and 1) a thermal resistance of 107˚C/W junction to ambient for the dual-in-line package and 2) a thermal resistance of 170˚C/W for the small outline package.

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How to get 74dB by LM386lm386.gif
LM386 is very popular IC also in Japan. It is used in Radio receiver. The power of it (500mW) is enough for the personal use. But sometimes, the gain of it (40dB) is not enough. Especially the direct conversion receiver depend on all of its gain on the audio amplifier. And therefore, we must stay sometimes the pre-amplifier before LM386. I will show you the way to get the...